Solid nitrilotriacetate-metal complexes

ABSTRACT

Solid nitrilotriacetate (NTA) - metal complexes having a metal to NTA molar ratio of more than 1.5 to 1, the metal being copper or manganese, are useful as micronutrients for plants and as catalysts in oxidation reactions. The solid complexes are prepared by reaction of a slurry of the metal salts with NTA in the molar ratio of 1:2 followed by drying. A small amount of mineral acid is an effective stabilizer for the solid complexes.

United States Patent Feiler et al.

[54] SOLID NITRILOTRIACETATE-METAL COMPLEXES Inventors: William A. Feiler, Kirkwood, Mo, 63122; Chung Yu Shen, St. Louis, Mo. 63166 Assignee: Monsanto Company, St. Louis, Mo.

Filed: Sept. 29, 1969 Appl. No.: 862,070

US. Cl ..260/429 R, 8/111, 71/27,

71/97, 260/429 J, 260/4381 Int. Cl. ..C07j 13/00, C07j 1/08 Field of Search ..260/429, 435.1

References Cited UNITED STATES PATENTS 11/1968 Kroll ..71/1 6/1963 Rembe ..71/l

OTHER PUBLICATIONS Brintzinger et al. 11, Z. fur Anorg. Chem. Vol. 254

[ 1 Aug. 29, 1972 Pfeiffer et al. Berichte 75 (19428) p. l- 12 Elovich et al. Chem. Abts. 56 (1961) column 15139 Brintzinger et al. I Z. fur Anorg. u. Allgem Chem. Vol. 249, p. 299- 307 Kirson et al. Bull. Soc. Chem. France, 1961, p. 1081- 1084 Primary Examiner-Tobias E. Levow Assistant Examiner-A. P. Demers Attorney-Herbert B. Roberts, Neal E. Willis and Robert M. Phipps [57] ABSTRACT Solid nitrilotriacetate (NTA) metal complexes having a metal to NTA molar ratio of more than 1.5 to 1,

, the metal being copper or manganese, are useful as 6 Claims, No Drawings SOLID NITRILOTRIACETATE-METAL COMPLEXES BACKGROUND 1. Field of the Invention This invention relates to solid complexes of nitrilotriacetate (hereinafter referred to as NT A) and a metal which is either copper or manganese having a metal to NTA molar ratio of more than 1.5 to 1 and which is useful as a micronutrient for plants and as a catalyst in chemical reaction.

2. Description of the Prior Art It is a well-annotated observation that the addition of chelated metal to the soil is a valuable treatment for overcoming chlorosis in plants. Although soils commonly contain large amounts of one or more of the metals, they are often unavailable, i.e., the compounds incorporating these metals do not release them to the plant. It has been found that these metals may be supplied to plants in an available form as respective metal sulfate. When the metals are added in the form of sulfate or equivalent compound relatively large quantities must be added due to the poor efficiency of the plant utilizing metal from these compounds. It is also been found that plants can more efficiently obtain these metals from some metal amine chelating compounds, e.g., the zinc salt of ethylene diaminetetraacetic acid. Use of these expensive metal chelating compounds have been limited to those few instances where, because of peculiar conditions of plant physiology or soil conditions, the plant is incapable of absorbing the trace metal when present in its natural form, or the less expensive metal sulfate.

In an effort to avoid the drawbacks of the use of ethylene diaminetetraacetic acid (EDTA) U.S. Pat. No. 2,891,854 disclosed the use of iron chelates of diethylenetriaminepentaacetic acid (DTPA). This patent taught that in marked contrast to the iron- EDTA chelate, the iron-DTPA chelate is much more effective in alkaline soils and much less toxic to the treated plant. In an attempt to meet the objections of the prior art, U.S. Pat. No. 3,115,511 proposed the use of iron chelate compositions which is the reaction product of a mole of an amino acid and a mole of powdered iron. Another approach to the problem is offered by British Pat. No. 1,094,781 wherein a combination of the metal salt and metal aminoacetate is employed, e.g., manganese nitrilotriacetate and manganese sulfate in a ratio of 1:3.

The metal chelate or complex, because of its greater solubility in a number of solvents, its stability, and its definite metal content, is a convenient form of catalyst in many chemical reactions. More specifically, it is often used in reactions where oxidation is taking place such as oxidation, bleaching, and drying of unsaturated linseed oil.

SUMMARY OF THE INVENTION It is an object of this invention to provide a composition which is more effective in supplying trace metal micro-nutrients to plants and to provide a composition useful as a catalyst. It is another object of this invention to provide a simple direct means of preparing process for preparing the composition of this invention. Other objects and advantages will become apparent upon inspection of this specification.

The invention sought to be patented, in its composition aspect, is described as residing in the concept of a plant micronutrient or a catalyst which is a chelate containing more than 1.5 moles of nitrilotriacetate and one mole of copper or manganese as the metal active ingredient.

The invention sought to be patented, in its process aspect, is described as residing in the concept of a reaction between nitrilotriacetate and a slurry of the metal salts, such as sulfate, chloride and nitrate. The products of this process are stabilized against oxidation by the admixing of small amounts of acid with the reactants.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The novel complexes of this invention are prepared by reacting a slurry of one mole of the metal salt with at least 1.5 moles and preferably 1.6 to 2.5 moles of nitrilotriacetate at a temperature from 0 to about 100C and preferably from about 50 to C. The time of the reaction will vary depending upon the temperature at which the reaction is carried out, time ranging from about 10 minutes for the manganese slurry at room temperature to about 3 minutes at 100C.

The material to be reacted needs to be in a finely divided state, the finer the particle size the more complete the reaction in a shorter period of time. It is particularly desirable that percent by weight of the reactants employed in the process of this invention pass through an U.S. sieve of 20 mesh.

The metal salt is preferred to be the easily commercial available form, such as sulfate, chloride, nitrate, carbonate, or oxide. The nitrilotriacetate is preferred as ammonium, sodium, potassium, or acid, or a mixture thereof.

For the process of this invention, water should be sparingly used. Thus, in the preparation of the manganese slurry an equal amount by weight of manganese monohydrate and water (preferably hot) is satisfactory. Lesser amounts of water, as low as 0.4 moles of water per mole of manganese, can be employed. In the preparation of the copper complex hot water or steam can be used to prepare a saturated copper sulfate solution at C. This saturated solution represents the maximum amount of water to be used in the process of this invention.

It is also been found useful to add small amounts of mineral acid such as sulfuric acid, hydrochloric acid, or nitric acid as an oxidation stabilizer for the novel complexes of this invention. It is particularly advantageous to employ the sulfuric acid in the preparation of the manganese complex. When adding sulfuric acid, the amount of 98 percent acid may vary up to 5 pounds for every 100 pounds of manganese complex formed, generally about 3.5 pounds is satisfactory. When properly stabilized, a 10 percent solution of the manganese complex has a pH of 7 to 8.

The novel solid complexes of this invention are useful as a micronutrient plant food and are applied as any other plant food. They may be admixed with other solids and applied as a conventional solid fertilizer or put into aqueous solution and applied either separately or with other liquid plant foods with conventional applicators such as sprays.

The metal chelate or complex of this invention, because of its greater solubility in a number of solvents, its stability, and its definite metal content, is a convenient form of catalyst in many chemical reactions. More specifically, it is often used in reactions where oxidation is taking place such as oxidation, bleaching, and drying of unsaturated linseed oil. As an oxidation reaction catalyst, the complexes of this invention are usually used in amounts less than 1.0 percent based on active metal content. Typical use ranges from about 0.25 to 1,000 ppm, the actual amount for any given application being easily ascertained by routine experimentation following standard procedures by those acquainted with the art. For example, 0.25 to ppm is advantageously used in textile bleaching.

The following examples are included to illustrate the preparation of the novel solid complexes of the present invention but are not to be considered limiting. Unless otherwise specified, all parts are by weight and all temperatures are degrees centigrade.

EXAMPLE 1 Na Mn(N(CH,COO) d 20* UP 8 05 l 1.0 46 7.69 l 1.5 59 6.74 13.1 97 6 13 14.4 20 5 67 15.6 12 5.21 17.0 28 5.18 17.1 24 5.03 17.6 38 4.48 19.8 18 4.06 21.9 38 3.96 22.5 22 3.67 24.2 40 3.43 25.9 17 3.41 26.1 17 3.36 26.5 22 with Cu aradiation EXAMPLE 2 Using the procedure of Example 1, 42.6 parts of copper sulfate pentahydrate, and 22 parts of water as a saturated solution plus 94 parts of sodium nitrilotriacetate monohydrate were charged to the reactor. 100 parts of Na Cu(N(CI-l COO) 3H 20 solid complex was obtained. A sodium sulfate byproduct of 24.25 parts was obtained while 34.3 parts of water were removed. The solid complex product had an X-ray diffraction pattern (first sixteen lines) as follows:

nitrilotriacetate 6.60 13.4 61 5.75 15.4 45 5.01 17.7 13 4.88 18.2 34 4.79 18.5 41 4.67 19.0 36 (est) 4.49 19.7 78 4.44 20.0 27 4.00 22.2 60 3.89 22.8 22 3.71 24.0 7 3.54 25.1 with Cu Karadiation EXAMPLE 3 The manganese complex of Example 1 was applied to various test plots of Pangola grass grown in a sandy loam found near Guatiles, Costa Rica to which various amount of lime was also added. The manganese complex successfully increased the amount of manganese uptake by the grass. The following manganese values were obtained.

Amount of Complex Applied Mn levels as kg of Mn/l-lectare Lime Avg. Soil Metric Tons/Hectare 0 60 ph ppm Mn in Pangola grass 0 460 700 767 5.39 5 13 3 153 177 5.99 10 63 67 47 6.46

EXAMPLE 4 EXAMPLE 5 Replicate unbleached cotton swatches (12.7 cm on each side) were bleached in hard water (hardness ppm) at 49C with 22.6 ppm active oxygen for 10 minutes in the presence of 0.15 percent by weight of a commercial laundry detergent based on anionic surfactants and sodium tripolyphosphate builder in a laboratory type miniature version of an agitator type washing machine. Color difference meter measurements were made on the swatches before and after bleaching. The improvement of using 0.5 ppm of the copper complex of Example 2 in the bleach bath was 53 percent over sodium NTA at 1 ppm and 22 percent over a complex of copper and sodium NTA in a 1:1 molar ratio at 0.5 ppm. Similar improvements were obtained using the manganese complex of Example 1 over sodium NTA or 1:1 molar ratio complex of manganese and sodium NTA.

The foregoing examples and method have been described in the foregoing specification for the purpose of illustration and not limitation. Many other modifications and ramifications will naturally suggest themselves to those skilled in the art based on this disclosure. These are intended to be comprehended as within the scope of this invention.

Having thus described our invention, what we desire to claim and secure by Letters Patent is:

1. Solid complexes of a potassium sodium or ammonium nitrilotriacetate and manganese wherein the molar ratio of nitrilotriacetate to manganese is from 1.5:1 to 2:1.

2. The solid complex of claim 1 wherein a percent by weight solution of said complex has a pH of from about 7 to about 8.

3. A method of preparing solid complexes of nitrilotriacetate and metal having a molar ratio of from 1.5:1 to 2:1 by reacting an admixture of a slurry of manganese or copper salts with a particulate ammonium, sodium or potassium nitrilotriacetate in a molar ratio of at least 1:15 at a temperature of about 0 to 100C said metal salt and said nitrilotriacetate having a particle size such that percent by weight pass through a U.S. Standard Sieve of 20 mesh.

4. The process of claim 3 wherein the metal salt is a sulfate and the nitrilotriacetate is sodium nitrilotriacetate.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,687,992 Datnd August 29, 1972 Inventofls) William i er It is certified" that error appears in the above-identifiad patent and that aid Letters Patent an hereby corrected as shown below:

I n column 5, line 31, the formula reading "Na Mn(N(Ch CO I should read ---Na Mn(N(CH CO In column 3, line 51, line reading "*With Cu a radiation" should read ---*With Cu Ken radiation---.

In column 3; line 58, end of formula reading "-BHEO" should In column 4, line 24, formula reading "ph" should read ---pH-- and should be placed under title "Avg. Soil".

Signed and sealed this 23rd day of January 1973* (SEAL) Attest:

EDWARD M.PLETCHER,JR. ROBERT GOTTSCHALK A'tcesting Officer Commissioner of Patents PC4050 UNITED STATES PATENT OFFICE CERTIFICATE 0F (WWI-IN Patent No. 5,687,992 Dated August 29, 1972 Inventor) William A. Feiler It is certified that error appear; in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In column 3, line Bl, the formula reading f'Na Mn(N(Ch CO should read -Na Mn(N(CH CO In column 3, line 51, line reading "*With Cu (1 radiation" should read -*With Cu Kon radiation-.

In column 3, line 58, end of formula reading "-BHEO" should read --'3H O---.

In column line 24, formula reading ph" shouldread -pH--- and should be placed under title Avg. Soil". I

Signed and sealed this 23rd day of Januar 1973..

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents 

2. The solid complex of claim 1 wherein a 10 percent by weight solution of said complex has a pH of from about 7 to about
 8. 3. A method of preparing solid complexes of nitrilotriacetate and metal having a molar ratio of from 1.5:1 to 2:1 by reacting an admixture of a slurry of manganese or copper salts with a particulate ammonium, sodium or potassium nitrilotriacetate in a molar ratio of at least 1:1.5 at a temperature of about 0* to 100*C said metal salt and said nitrilotriacetate having a particle size such that 95 percent by weight pass through a U.S. Standard Sieve of 20 mesh.
 4. The process of claim 3 wherein the metal salt is a sulfate and the nitrilotriacetate is sodium nitrilotriacetate.
 5. The method of claim 3 wherein the reaction is carried out in the presence of a stabilizing amount of a mineral acid and wherein said metal salt is manganese sulfate.
 6. The method of claim 5 wherein the mineral acid is sulfuric acid. 